In one word, the NSTA conferences are AMAZING - particularly the spring national conference!
You will come away with ideas, resources, and contacts that will give you a professional boost and make you better teacher. Even after 27 years of teaching I was able to walk away from a national conference with dozens of new ideas that I could incorporate into lessons the day I got back to my classroom. The vendor area is mind-blowing and you should bring an extra large suitcase for all resources you will walk away with! I also recommend you get involved in NSTA somehow - via a committee, as a director or as a writer.
My biggest regret is that I should have gone to more in my career. Something to do at least every 5 years if you can manage.
Considering the current COVID situation I worry that conferences like this may become a thing of the past. I certainly hope not.